engleski

IMPACT OF CORONARY FLOW ON PARAMETERS OF A LUMPED MODEL OF THE ARTERIAL TREE

The arterial tree is a network of visco-elastic blood vessels, which delivers blood to the whole body. The simplest models of the arterial tree are lumped models, which describe the arterial tree as a system of compliant chambers. The lumped models are attractive for clinicians because they describe the function of the whole arterial tree in terms of simple parameters such as compliance, resistance, and inertance. The main purpose of lumped models is in modeling the arterial input impedance (the pressure to flow ratio in the frequency domain) as an afterload to the left ventricle. The lumped models are used in defining the total arterial compliance and resistance, which can explain changes of arterial trees due to ageing and disease. The concept of input impedance requires a linear model of the arterial tree. The model of the coronary circulation is complex and highly non-linear, therefore it should be excluded from the arterial tree. By doing this, the beginning of the arterial tree becomes the ascending aorta. During diastole Qav is equal to zero, it is clear that Qcor comes from the compliant aorta. Therefore, the measured coronary flow should be included in the arterial tree model. The goal is to compare parameters of the arterial tree models with and without coronary flow at the inlet of the arterial tree. The models will be applied to three typical subjects (adolescent, middle-aged and elderly) with recorded data. The model parameters are obtained by minimizing the pressure RMSE, with prescribed measured flows at the arterial tree inlet. The impact of coronary flow will be quantified it terms of a changes of RMSE and model parameters. The inclusion of the coronary flow into the lumped model of the arterial tree, does not significantly improve the model because its impact on the model parameters is small.

coronary flow; lumped model; arterial tree

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